We have operated on two cases of slipped ribs syndrome( SRS). Both patients were men in their 40s with a history of right thoracic trauma who were referred to us because of unexplained lower thoracic pain. The left rib was positive for hooking maneuver (lift test), and dynamic ultrasonography showed narrowing of the intercostal space, which led to the diagnosis of SRS. in the first case, the tip of the ninth rib cartilage was excised, and the ninth and tenth rib cartilages were sutured and fixed with No.2 fiber wire in two places with Z sutures. In the second case, the tip of the ninth rib cartilage was excised, the eighth and ninth ribs and the ninth and tenth ribs were fixed with No.2 fiber wire with Z sutures as in the first case, and a 0.7 mm thick poly-L-lactide (PLLA) plate was added between the eighth and tenth rib cartilages. In both cases, the postoperative course was good and the pain disappeared. SRS should be recognized as a disease and surgical treatment should be used as therapy.